Proposed here is the third wave of a prospective study of drug abuse, treatment experiences and health in a homogeneously urban non-hispanic black sample, males and females. The research was begun in 1968-70 when the panel were adolescents aged 12-17. At second interviews in 1975-76, they were ages 18-23. In the proposed third wave in 1983 the panel will be aged 26-31. Using quasi experimental research methods which the well-preserved natural community sample makes possible, and building upon findings from the prior two study periods, three substudies have been designed to seek regularities in drug treatment behavior and antecedent drug abuse. Two of them test an elaborated availability-proneness model of drug abuse: STUDY ONE: CHANGING PATTERNS IN DRUG ABUSE AND TREATMENT IN RELATION TO HEROIN AVAILABILITY tests annual rates of drug abuse and treatment against changing price-purity of heroin over the thirteen year period, 1970-1982, disentangling effects from aging, cohort and general economic conditions. STUDY TWO: PATHWAYS TO TREATMENT analyzes transitions in alternative trajectories of drug abuse and treatment, in order to identify contextual supports (roles and interpersonal networks) and personal supports for, and barriers to, desirable choices (i.e., drug avoidance, natural cessation, treated cessation). STUDY THREE: LONG TERM HEALTH EFFECTS FROM DRUG INVOLVEMENT includes a secondary study of the interrelation between drug treatment and general health care services utilization. The three studies are intended to improve forecasting of treatment needs, identify race appropriate goals and processes in treatment, in outreach and in health care, respectively, in a high risk urban black population.